Mongol invasions of Japan

The Mongol invasions of Japan occurred in 1274 and 1281 when the Mongol Yuan emperor Kublai Khan twice attempted to conquer the Japanese islands with strong naval forces. However, his fleets were destroyed by "divine winds" both times, and Japan was saved from Mongol conquest.

Background
In 1266, Yuan Mongol emperor Kublai Khan sent the first Mongol envoys to Japan to invite the Japanese to offer tribute. The Japanese regent Hojo Tokimune ignored the envoys over the next few years, and the silence was an affront to the powerful Mongol Empire. In 1268, Kublai Khan began preparations for an amphibious naval invasion of Japan, using experienced Korean sailors and vessels (Korean provisions) to prepare an invasion. Hojo Tokimune sent Japanese warriors to Kyushu to prepare to defend Japan from the impending Mongol attack. The fall of the key Song fortress at Xiangyang in 1273 freed up Mongol naval forces for the amphibious assault, and Kublai prepared a force of 15,000 Mongol, Chinese, Khitan, and Jurchen soldiers, 8,000 Korean troops, and 7,000 Korean sailors and a fleet of 300 warships and 500 smaller vessels. The Mongols were overconfident about their chances of a swift victory, having already conquered all of China and Korea.

1274
In 1274, the Mongol fleet departed from Korea and fell upon the small Japanese islands of Tsushima and Iki, overrunning the sparsely-defended settlements with little fighting. The Mongols set sail for Kyushu's Hakata Bay in November 1274, where they faced as few as 3,600 Japanese warriors. The Yuan armada landed on the shore of Kyushu, leading to the first battle for Hakata Bay. The Japanese opened battle with their arrows, but the Mongols laughed at the arrows and scared off the Japanese horses with their war drums. The Japanese fiercely fought along their seawall, and the Mongols were unable to bring their fearsome cavalry to bear, instead using bombs against the Japanese. The Mongols eventually broke through the wall and burned the nearby town of Hakata. However, the site of the Mongol camp, Akasaka, proved undefendable, and Japanese archers wounded Liu Fuheng in the face with an arrow and captured his horse. The Mongols inflicted heavy losses on the Japanese before withdrawing, and a great typhoon destroyed much of the Mongol fleet and forced them to retreat. In 1275, Kublai Khan's new envoys to Japan were executed, ensuring a Mongol return.

1281
In 1279, Kublai Khan completed his conquest of southern China, so he decided to use newly-conquered Chinese troops for his invasion of Japan, as Korea had been economically devastated by the first invasion. Hojo Tokimune prepared and extended the seawall around Hakata Bay for 20 kilometers and prepared a larger defense. Kublai gathered the largest seaborne invasion before D-Day in 1944, preparing a fleet of 100,000 troops (the northern fleet had 40,000 Mongols, Jurchen, northern Chinese, and Koreans on 900 ships; the southern fleet had 60,000 Chinese troops aboard 3,500 vessels) aboard repurposed river ships. The Mongol southern fleet was delayed due to their commander's illness and food spoilage, so the northern fleet set out alone and took Iki on 12 June 1281. Two weeks later, the Mongol fleet found the shores of Kyushu well-defended at Munakata. The southern fleet arrived in July, attacking the Japanese at Shima. Language barriers and political tensions between the Mongolic-Korean and Chinese forces led to a lack of coordination between the invasion forces, and neither the Mongols nor the Japanese were able to gain the upper hand over the next month. The Japanese launched a surprise attack on the Mongol fleet with ambush troops and fire ships. On 15 August 1281, a new typhoon destroyed the Yuan fleet, which was caught between the storm and the coast. A few Korean ships escaped slamming against the rocks, but a third of the northern fleet and over half of the southern were destroyed, and the second Mongol invasion failed. The captured Song troops were executed by the Japanese, while the remainder limped back to China.

Aftermath
The aura of Mongol invincibility was tarnished by the failed invasions, and the second invasion was a massive expenditure of men and resources who now lay at the bottom of the ocean. Korea's economy was especially devastated, so Kublai Khan had to turn to his (corrupt) financial advisors Ahmad Fanakati and Li Shih-jung for help. A new era of financial mismanagement followed, and Kublai withdrew after his wife and heir died. Kublai fell into womanizing, overeating, obesity, and depression, and Kublai would never launch another invasion of Japan, while his invasions of Burma, Vietnam, and Java all failed.